Percutaneous vertebroplasty (PVP) is a therapeutic procedure that involves injection of bone cement into a vertebral body to confer strength and stability to the vertebra. Kyphoplasty is a related therapeutic procedure. Both procedures are performed minimally invasively and are established techniques for treatment of painful, osteoporotic compression fractures. See, e.g., Gangi, A., et al. Percutaneous Vertebroplasty Guided by a Combination of CT and Fluoroscopy, AJNR 15:83-86, January 1994; Deramond, H., et al., Percutaneous Vertebroplasty, Seminars In Musculoskeletal Radiology, Vol. 1, No. 2, 1997: 285-295; Resnick, D. K. and Garfin, S. R., Vertebroplasty and Kyphoplasty, 2005, each incorporated herein by reference its entirety.
Both procedures have been developed for use with bone cements, for example polymethylmethacrylate (PMMA). Exemplary bone cements include: Confidence Cement System® (Disc-O-Tech, Monroe Township, N.J.), Palacos® Bone Cement (Zimmer, Inc., Warsaw, Ind.), Surgical Simplex®, Spineplex™ (Styker Corp., Kalamazoo, Mich.), KyphX® HV-R™ (Kyphon, Inc., Sunnyvale, Calif.), and Cortoss® (Orthovita, Inc., Malvern, Pa.). (See also, Lewis, G., Injectable Bone Cements for Use in Vertebroplasty and Kyphoplastry: State-of-the-Art Review, J. Biomed. Mater. Res. B. Appl. Biomater., 2006 February; 76(2): 456-68). These cements are generally available as two-component systems that, upon mixing, polymerize and harden. As the components polymerize, the viscosity of the resulting composition increases dramatically over a period of a few minutes. Typically, the medical professional has a limited amount of time, once the components are mixed, to load the resulting composition into a syringe, and deliver the composition to the surgical situs, before the composition becomes too viscous to administer. At the same time, the medical professional must be vigilant and avoid leakage of the cement outside of the surgical situs, as such leakage can cause patient injury or fatality.
Devices that reduce the number of steps required to prepare and deliver these cements into the surgical site are needed in order to decrease procedure time and minimize surgical risks to the patient. Reducing the number of steps also provides additional assurances of sterility. In addition, because the procedures are typically carried out under fluoroscopy, devices that remove the physician's hands from the imaging field are needed. Also desirable is an ergonomic device that facilitates hand operation, so that physicians can devote their attention to monitoring the flow of the material into bone.